s = input()
n = len(s)
res = 10 ** 100
for i in range(n):
    if s[i] != 'c':
        continue
    cnt = 0
    for j in range(i + 1, n):
        if s[j] == 'w':
            cnt += 1
        if cnt == 2:
            res = min(res, j - i + 1)
            break
if res == 10 ** 100:
    print(-1)
else:
    print(res)